Nonglare illuminated panel



Dec. 16, 1952 Filed April 19, 1949 2 Sl-lEETS-SI-IEET 1 1 imam v Dec.16, 1952 PETER ETAL 2,622,137

NONGLARE ILLUMINATED PANEL Filed April 19, 1949 2 SHEETS-SHEET 2 w MMWWMQQTW Patented Dec. 16, 1952 UNITED STATES PATENT OFFICE Leslie HurstPeter and Edward Alfred Sheppard, Kings Cross, London, England,assignors to Westinghouse Brake and Signal Company Limited, London,England Application April 19, 1949, Serial No. 88,334;

In Great Britain May- 13, 1948 e This invention relates to mimic diagrampanels for railway signalling systems of thekind arranged to provide arepresentation of railway trackand signal layouts for the purpose ofcontrol or information, and has for its object to provide an improvedpanel of this character.

Mimic diagram panels are now widely employed in railway signal cabins,for example, to provide a signalman with a complete and compactrepresentation of the track layout controlled from the cabin.

As hitherto arranged the diagram panel is plane and is usually mountedabove a control panel or console and in the case of complicated layoutsor networks the vertical dimension of the panel is somewhat considerableso that the extreme edges of the panel subtend a large angle at theobservers eye and render observation inconvenient and fatiguing.

Furthermore a plane panel has the disadvantage that light rays for anynatural or artificial source are liable to be reflected in a directionwithin the range of vision of the observer.

According to the invention, the cross-sectional contour of the panel iscurved so as to present a concave surface to the observer the curvaturebeing such that any light from an extraneous source is reflected fromthe surface of the panel to a point or points invisible to the observer.

The panel, owing to its concave form, enables the whole representationcarried thereby to be viewed by an observer through reduced angle ofvision as compared with a plane panel, while reflection from anextraneous source of light cannot interfere with observation.

The invention is illustrated by way of example in the accompanyingdrawings Figures 1 and 2 of which are diagrammatic views in sideelevation of mimic diagram panels arranged in accordance with two formsof the invention respectively.

Fig. 1a shows the front elevation of the mimic diagram shown in Fig. 1;

Referring now to Figure 1 and 1A, the diagram panel I is shown asmounted in a trough or casing 2 forming the upper part of a. frame orhousing 3 for the control panel or console 4 for the track or conductorlayout a mimic representation 20 of which is shown in Fig. 1A and borneby the panel I.

The control panel or console bears devices to be manipulated by anoperator positioned in front thereof for the control in any suitablemanner of the associated track switches and signals.

It will be seen that the panel I subtends at the eye of the controloperator indicated at 5,

3 Claims. (01. 177 311) -i2 an angle ofvision a, the panel I presentingaconcave surface to' the operators eye with a radius of curvatureindicated by the dotted. line 6 and a centre of curvature at the pointI. The dotted lines 8, 9 including the angle of vision (1., indicatesthe limiting lines of sight of the panel by the operator, and afterreflection from the concave surface of the panel I these lines of sightare represented by the dotted lines I0, I I, respectively which as willbe seen in the figure converge towards a point beyond an opaque screenl2. The latter is blackened so as to render the screen highlynon-reflecting with the result that any image formed by light from anextraneous source, after reflection from the surface of the panel 1 isprevented from being seen by the operator.

In other words all real images produced by reflection from the surfaceof the panel which are outside the lines of sight I0, II are for thisreason necessarily invisible to the operator while the formation of anysuch image within the lines of sight I0, II is prevented by the opaquenonreflecting screen l2 which intercepts any light rays tending to formthis image.

Extraneous natural or artificial light is thus prevented from reachingthe eye of the operator by reflection from the panel I and therepresentation 20 of the track layout borne by the panel is clearlyvisible to the operator under all conditions.

In the modification shown diagrammatically in Figure 2 the diagram panelI is so located in the frame 3 that the surface of the panel constitutesan extension of the surface of the control panel or console =4, the twosurfaces merging more or less smoothly into one another. The lines ofsight H), II forming the limits of the angle of vision a. of theoperators eye 5 after reflection from the panel I converge towards apoint above the trough 2 containing the panel I and are intercepted byan opaque non-reflecting screen l3, the optical effect of thismodification being similar to that of the arrangement of Figure 1already described.

In both forms of the invention the panel I is preferably arranged to beilluminated by internal reflection from a source of light l4 at theupper edge of-the panel as described in the specification of ourco-pending U. S. Patent No. 2,591,864 issued on April 8, 1951.

The invention is evidently not limited to any particular construction orarrangement of the diagram or control panel.

Having thus described our invention what we claim is: I

1. Control apparatus for railway signalling systems, comprising incombination, a control panel bearing devices to be manipulated by anoperator positioned in front thereof; a non-reflecting opaque screen;and a concave diagram panel situated above and behind said control paneland curved in vertical cross-section such that the image of the eye ofsaid observer reflected at the surface of the diagram panel is absorbedby said screen.

2. Control apparatus for railway signalling systems, comprising incombination, a control panel bearing devices to be manipulated by anoperator positioned in front thereof; a nonreflecting opaque screen inrear of said control panel and invisible from the position of saidoperator; and a concave diagram panel situated above and behind saidcontrol panel and curved in vertical cross-section such that all rays oflight passing through the position of the eye of said observer andreflected at the surface of the said diagram panel are reflected on tosaid screen.

3. Control apparatus for railway signalling systems, comprising incombination, a control panel bearing devices to be manipulated by anoperator positioned in front thereof; a nonreflecting opaque screen; anda concave diagram panel curved in vertical cross-section situated aboveand behind said control panel and having said screen arranged along thetop horizontal edge thereof, such that all rays of light passing throughthe position of the eye of said observer and reflected at the surface ofsaid diagram panel are reflected on to said screen.

LESLIE HURST PETER.

EDWARD ALFRED SHEPPARD.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,168,751 Schuhmann Jan. 18, 19161.681349 Krause Aug. 21, 1928 1,737,520 Richardson, Jr Nov; 26, 19291,953,555 Frey Apr. 3, 1934 2,003,735 Brown et al June 4, 1935 2,159,095Madan May 23, 1939

